How to handle "Warning: Function created with compilation errors." when create Oracle function.

For example (MYFUNC.sql):

1 CREATE OR REPLACE FUNCTION MYFUNC

2 RETURN NUMBER AS

3 MYVAR NUMBER;

4 BEGIN

5 SELECT COUNT(*) INTO MYVAR FROM MYTAB;

6 RETURN MYVAR;

7 END MYFUNC;

8 /

$ sqlplus $LOGIN @MYFUNC.sql

sql*Plus: Release 12.1.0.1.0 Production on Mon May 25 00:26:09 2015

Copyright (c) 1982,2013,Oracle. All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Partitioning,OLAP,Data Mining and Real Application Testing options

Warning: Function created with compilation errors.

sql>

sql> show errors;

Errors for FUNCTION MYFUNC:

LINE/COL ERROR

-------- -----------------------------------------------------------------

5/3 PL/sql: sql Statement ignored

5/35 PL/sql: ORA-00942: table or view does not exist

sql>

It's mean that table MYTAB does not exists.

sql> CREATE TABLE MYTAB(A INT);

Table created.

sql> @MYFUNC.sql

Function created.